Radial sealing bar for a rotary piston internal combustion engine

ABSTRACT

A radial sealing bar for a rotary piston internal combustion engine of trochoidal construction which is guided within an axially parallel groove of a piston and is forced radially outwardly by at least one leaf spring; the sealing bar is thereby provided with at least one hollow space with an opening, into which a leaf spring projects through the opening, whereby the leaf spring rests against the groove bottom in such a manner that the leaf spring is supported against the upper wall portion of the hollow space.

United States Patent Lamm Oct. 28, 1975 RADIAL SEALING BAR FOR A ROTARY3,667,877 6/1972 Lamm 418/121 3,712,767 1/1973 'Beutter 418/121 PISTONINTERNAL COMBUSTION ENGINE Inventor: Heinz Lamm, Esslingen-St.

Bernhardt, Germany Assignee: Daimler-Benz Aktiengesellschaft,

Germany Filed: Oct. 4, 1974 Appl. No.: 512,350

Foreign Application Priority Data Oct. 9, 1973 Germany .l 2350572 US. Cl418/122; 418/122 Int. Cl. F01C 19/02 Field of Search 418/121, 122, 123,266

References Cited UNITED STATES PATENTS 7/1944 Davidson 418/122 PrimaryExaminer--C. J. Husar Assistant Examiner-Leonard Smith Attorney, Agent,or Firm-Craig & Antonelli [5 7] ABSTRACT A radial sealing bar for arotary piston internal combustion engine of trochoidal constructionwhich is guided within an axially parallel groove of a piston and isforced radially outwardly by at least one leaf spring; the sealing baris thereby provided with at least one hollow space with anopening, intowhich a leaf spring projects through the opening, whereby the leafspring rests against the groove bottom in such a manner that the leafspring is supported against the upper wall portion of the hollow space.

25 Claims, 4 Drawing Figures U.S.' Patent Oct. 28, 1975 3,915,600

FIG],

RADIAL SEALING BAR FOR A ROTARY PISTON INTERNAL COMBUSTION ENGINE Thepresent invention relates to a radial sealing bar for a rotary pistoninternal combustion engine, especially of trochoidal type ofconstruction, which is guided in an axially parallel groove of a pistonand is pressed outwardly in the radial direction by at least one leafspring.

It is known to arrange leaf springs underneath the sealing bar in thepiston groove between two small leg portions of corner parts of thesealing bar in order to prevent a displacement of the leaf springs inthe longitudinal direction of the groove. Such arrangements entail thedisadvantage with the use of relatively heavy sealing bars--regardlessof whether of one-piece or multi-partite construction--that by reason ofthe high load of the corner parts by the springs, br'eakages of thesmall leg portions which occur frequently cannot be avoided.

The present invention is concerned with the task to eliminate theshortcomings and drawbacks which have occurred in the prior art springarrangement and to provide a spring construction which additionallyenables a lesser assembled structural height of the sealing bar systemwithin the piston groove.

The underlying problems are solved according to the present invention inthat the sealing bar is provided with a hollow space having at least oneopening, into which the leaf spring resting at the groove bottom of thegroove projects through the opening in such a manner that it supportsitself at the upper wall portion of the hollow space.

The sealing bar which is constructed hollow, will become lighter byabout one-half as regards weight; additionally, it will also become moreelastic and impactresistant. Furthermore, the sensitive small legportions at the corner parts may be dispensed with because already thehollow space serves as limitation against lateral displacement of theleaf spring.

In order to facilitate the assembly, to prevent the spring from fallingout of the sealing bar and additionally to achieve a saving in weight ofthe sealing bar which is as large as possible, it is proposed accordingto the present invention that the hollow space extends approximatelyover the entire length of the sealing bar and in that--as viewed in thelongitudinal direction of the sealing bar--two openings or apertures areprovided arranged one behind the other, through which extends the leafspring.

In one advantageous construction according to the present invention, theleaf spring which is bent or curved bow-like, may support itself withits free ends at the upper wall portion in the hollow space of thesealing bar and with its curved portion at the groove bottom of thegroove.

Both this arrangement as also the arrangements to be describedhereinafter may be used for sealing bars which are constructed either inone piece or are provided with corner parts.

According to the present invention, the leaf spring which is curved orbent bow-like may support itself with its curved or arcuate portion atthe upper wall portion in the hollow space of the sealing bar and withits free ends at the groove bottom of the groove.

Only for sealing bars with corner parts provision is made according tothe present invention to construct the leaf spring three-arched in sucha manner that the center arc abuts at the upper wall portion in thehollow space and that the adjacent arcs adjoining the center arc aresupported at the groove bottom while the free ends of this leaf springare supported underneath the corner parts.

A lifting off from the casing contact surface or a falling down onto thegroove bottom is thus avoided in connection with the corner parts.

It is additionally proposed as a further embodiment according to thepresent invention for multi-partite sealing parts to provide the cornerparts thereof with small leg portions and to arrange underneath the arcof the leaf spring projecting into the hollow space of the sealing bar,a second leaf spring provided with a larger radius of curvature whosefree ends are supported at the corner parts in front of or ahead of therespective small leg portions.

Since these small leg portions of this sealing bar system are notexposed to as large loads and stresses, the second spring is constructedrelatively weak by reason of the relatively light-weight sealing bar andadditionally by the arrangement of the first spring. The second springhas only the task to press the corner parts radially outwardly.

In connection with the two last-mentioned embodiments, frictionvibrations and chatter marks are farreachingly avoided since theindividual sealing bar parts vibrate independently of one another andare thus damped better. Furthermore, the sealing bar parts do not liftoff from the casing contact or running surface which means a bettergas-tightness of the engine.

For purposes of avoiding scoring and for reasons of better slideproperties, the leaf springs are constructed according to the presentinvention at the free ends thereof so as to be bent either outwardly orinwardly.

Accordingly, it is an object of the present invention to provide aradial sealing bar for a rotary piston internal combustion engine whichavoids by simple means the aforementioned shortcomings and drawbacksencountered in the prior art.

Another object of the present invention resides in a radial sealing barfor a rotary piston internal combustion engine which avoids failures inoperation, particularly breakages of small leg portions serving asspring abutments.

A further object of the present invention resides in a sealing bar for arotary piston internal combustion engine which enables a construction ofthe sealing bar system which is of lesser height within the pistongroove.

Still a further object of the present invention resides in a radialsealing bar for a rotary piston internal combustion engine which isconsiderably lighter in weight, offers greater elasticity and exhibitsgreater impact resistance than the prior art constructions.

A further object of the present invention resides in a radial sealingbar for a rotary piston internal combustion engine which permits theelimination of the small leg portions, particularly at the corner partsof the radial selaing bar which are sensitive to breaking or otherdamages.

Another object of the present invention resides in a radial sealing barfor a rotary piston internal combustion engine which facilitatesassembly and enables a substantial saving in weight of the sealing bar,yet is simple in construction and easy to install.

A still further object of the present invention resides in a radialsealing bar which far-reachingly avoids frictional vibrations andchatter marks as well as scoring.

These and other objects, features and advantages of the presentinvention will become more apparent from the following description whentaken in connection with the accompanying drawing which shows, forpurposes of illustration only, several embodiments in accordance withthe present invention, and wherein:

FIG. 1 is a somewhat schematic partial crosssectional view through aone-piece sealing bar with a leaf spirng having a single arc inaccordance with the present invention for a rotary piston internalcombustion engine;

FIG. 2 is a somewhat schematic partial crosssectional view through amulti-partite sealing bar in accordance with the present inventionprovided with corner parts and a single-arched leaf spring;

FIG. 3 is a somewhat schematic partial crosssectional view through amulti-partite sealing bar in accordance with the present invention witha threearched leaf spring; and

FIG. 4 is a somewhat schematic partial crosssectional view through amulti-partite sealing bar with a double spring arrangement in accordancewith the present invention.

Referring now to the drawing wherein like reference numerals are usedthroughout the various views to designate like parts, and moreparticularly to FIG. 1, a unitary or one-piece radial sealing bargenerally designated by reference numeral 1 for a rotary piston internalcombustion engine of trochoidal construction which essentially consistsof a housing casing 2, of side parts 3 and 4 and of a polygonal piston 5rotating within these housing parts is illustrated in this figure. Sincethe rotary piston internal combustion engine of trochoidal constructionis of conventional design, a detailed description thereof is dispensedwith herein for the sake of simplicity. The sealing bar 1 guided withina groove 6 arranged in the corners of the piston 5 is provided with ahollow space 7 which extends approximately over the entire length of thesealing bar 1. Two openings or apertures 8 and 9 are provided at thebottom side of the sealing bar I, which serve as passage for a leafspring 10 bent in the manner of an arc or bow. The free ends 11 and 12of the leaf spring 10 abut at the upper wall portion 13 within thehollow space 10 of the sealing bar 1 whereas the arcuate portion 14 ofthe sealing bar 1 is supported at the groove bottom 15 of the groove 6.

The embodiment according to FIG. 2 differs from the embodimentillustrated in FIG. 1 in that the sealing bar I is constructedmuIti-partite and consists of a trapezoidally shaped center part l6-asviewed in longitudinal cross section, whose shorter one of the twoparallel sides is constructed as sealing bar cap or head portion andincludes two corner parts 17 and 18. The corner parts 17 and 18 are soformed that they in unison with the center part 16 are pressed radiallyoutwardly against the casing running or contact surface of the housingcasing 2 by the spring force, whereby only the center part 16 isprovided with a hollow space 19 for the single-arched spring 10.

The sealing bar 1 according to FIG. 3 is provided with a center part 21,again of trapezoidal shape, whose longer one of the two parallel sidesincontrast to the center part 16 of FIG. 2is constructed as sealing barcap or head portion. The center part 21 as well as the corner parts 22and 23 adjacent the center part 21 are retained by a single three-archedleaf spring 24 which is supported with its centrally disposed arcuateportion 25 at the upper wall portion within the hollow space of thecenter part 21 whereas it is supported with its two outwardly disposedarcuate portions 26 and 27 at the bottom groove 15 of the groove 6 andwith its free ends 28 and 29 at the respective corner part 22 and 23.

The sealing bar 1 according to FIG. 4 is of similar construction as thesealing bar previously described in connection with FIG. 3. Theessential difference resides in that the corner parts 30 and 31 of thisthreepartite sealing bar 1 are provided with samll leg portions 32 and33, respectively. The center part 34 is retained in its position by theleaf spring 10-this spring corresponds to the leaf springs illustratedin FIGS. 1 and 2whereas for avoiding a lifting off from the casingrunning surface 20, the corner parts 30 and 31 are forced against thecasing contact surface by a second leaf spring 35 bent or curvedbow-like, for which the small leg portions 32 and 33 are provided at thecorner parts 30 and 31 as lateral limitation or stop. The leaf spring 35provided with the larger radius of curvature is arranged underneath thefirst leaf sping 10. Both leaf springs are supported together at thegroove bottom 15 of the groove 6.

While I have shown and described several embodiments in accordance withthe present invention, it is understood that the same is not limitedthereto but is susceptible of numerous changes and modifications asknown to those skilled in the art. For example, the free ends of theleaf spring may be bent inwardly or outwardly, as the case may be.Furthermore, the arrangement of FIG. 1 may be reversed so that thearcuate portion of the leaf spring is supported against the upper wallwithin the hollow space whereras the free ends of the springs aresupported in the groove bottom. Such construction is particularlysuitable for a one-piece radial sealing bar arrangement. Consequently, Ido not wish to be limited to the details shown and described herein butintend to cover all such changes and modifications as are encompassed bythe scope of the appended claims.

I claim:

I. A radial sealing bar for a rotary piston internal combustion engine,said radial sealing bar being guided within a groove means of a pistonand being forced outwardly substantially in the radial direction by atleast one leaf spring means, characterized in that the sealing bar isprovided with at least one hollow space having an aperture means, theleaf spring means which abuts at the groove bottom of the groove meansprojecting into the hollow space through the aperture means in such amanner that the leaf spring means is also supported against the upperwall portion of the hollow space.

means, the arcuate portions adjoining the center arcuate portion beingsupported at the groove bottom and the free ends being supported at thesealing bar.

4. A radial sealing bar according to claim 1, of multipartiteconstruction which includes corner parts, characterized in that the freeends of the leaf spring means are supported under the corner parts.

5. A radial sealing bar according to claim 1, of multiparti teconstruction which includes small leg portions, characterized in thatunderneath the arcuate portion of the leaf spring means projecting intothe hollow space means of the sealing bar, a further leaf spring meansis provided having a larger radius of curvature, whose free ends aresupported at the sealing bar ahead of the respective small leg portionsthereof.

6. A radial sealing bar according to claim 5, characterized in that thesealing bar includes corner parts provided with said small leg portionsand in that the free ends of the further leaf spring means are supportedat said corner parts ahead of the small leg portions.

7. A radial sealing bar according to claim 1, characterized in that thefree ends of the leaf spring means are bent.

8. A radial sealing bar according to claim 7, characterized in that thefree ends of the leaf spring means are bent outwardly.

9. A radial sealing bar according to claim 7, characterized in that thefree ends of the leaf spring means are bent inwardly.

10. A radial sealing bar according to claim 1, characterized in that theleaf spring means is curved arcuately shaped.

11. A radial sealing bar according to claim 10, characterized in thatthe leaf spring means is supported with its free ends at the upper wallportion within the hollow space means of the sealing bar and with itsarcuate portion at the groove bottom of the groove means.

12. A radial sealing bar according to claim 10, characterized in thatthe leaf spring means is supported with its arcuate portion at the upperwall portion in the hollow space means of the sealing bar and with itsfree ends at the groove bottom of the groove means.

13. A radial sealing bar according to claim 1, characterized in that therotary piston internal combustion engine is of trochoidal construction.

14. A radial sealing bar according to claim 13, characterized in thatthe groove means is axially parallel.

15. A radial sealing bar according to claim 14, characterized in thatthe hollow space means extends approximately over the entire length ofthe sealing bar and is provided--as viewed in the longitudinal directionof the sealing bar--with two aperture means arranged one behind theother, through which projects the leaf spring means.

16. A radial sealing bar according to claim 15, characterized in thatthe leaf spring means is curved arcuately shaped. v

17. A radial sealing bar according to claim 16, characterized in thatthe leaf spring means is supported with its free ends at the upper wallportion within the hollow space means of the sealing bar and with itsarcuate portion at the groove bottom of the groove means.

18. A radial sealing bar according to claim 16, characterized in thatthe leaf spring means is supported with its arcuate portion at the upperwall portion in the hollow space means of the sealing bar and with itsfree ends at the groove bottom of the groove means.

19. A radial sealing bar according to claim 16, characterized in thatthe leaf spring means is constructed three-arched, the center arcuateportion being supported at the upper wall portion of the hollow spacemeans, the arcuate portions adjoining the center arcuate portion beingsupported at the groove bottom and the free ends being supported at thesealing bar.

20. A radial sealing bar according to claim 16, of multi-partiteconstruction which includes corner parts, characterized in that the freeends of the leaf spring means are supported under the corner parts.

21. A radial sealing bar according to claim 16, of multi-partiteconstruction which includes small leg portions, characterized in thatunderneath the arcuate portion of the leaf spring means projecting intothe hollow space means of the sealing bar, a further leaf spring meansis provided having a larger radius of curvature, whose free ends aresupported at the sealing bar ahead of the respective small leg portionsthereof.

22. A radial sealing bar according to claim 21, characterized in thatthe sealing bar includes corner parts provided with said small legportions and in that the free ends of the further leaf spring means aresupported at said corner parts ahead of the small leg portions.

23. A radial sealing bar according to claim 21, characterized in thatthe free ends of the leaf spring means are bent.

24. A radial sealing bar according to claim 23, characterized in thatthe free ends of the leaf spring means are bent outwardly.

25. A radial sealing bar according to claim 23, characterized in thatthe free ends of the leaf spring means are bent inwardly.

1. A radial sealing bar for a rotary piston internal combustion engine,said radial sealing bar being guided within a groove means of a pistonand being forced outwardly substantially in the radial direction by atleast one leaf spring means, characterized in that the sealing bar isprovided with at least one hollow space having an aperture means, theleaf spring means which abuts at the groove bottom of the groove meansprojecting into the hollow space through the aperture means in such amanner that the leaf spring means is also supported against the upperwall portion of the hollow space.
 2. A radial sealing bar according toclaim 1, characterized in that the hollow space means extendsapproximately over the entire length of the sealing bar and isprovided-as viewed in the longitudinal direction of the sealing bar-withtwo aperture means arranged one behind the other, through which projectsthe leaf spring means.
 3. A radial sealing bar according to claim 1,characterized in that the leaf spring means is constructed three-arched,the center arcuate portion being supported at the upper wall portion ofthe hollow space means, the arcuate portions adjoining the centerarcuate portion being supported at the groove bottom and the free endsbeing supported at the sealing bar.
 4. A radial sealing bar according toclaim 1, of multi-partite construction which includes corner parts,characterized in that the free ends of the leaf spring means aresupported under the corner parts.
 5. A radial sealing bar according toclaim 1, of multi-partite construction which includes small legportions, characterized in that underneath the arcuate portion of theleaf spring means projecting into the hollow space means of the sealingbar, a further leaf spring means is provided having a larger radius ofcurvature, whose free ends are supported at the sealing bar ahead of therespective small leg portions thereof.
 6. A radial sealing bar accordingto claim 5, characterized in that the sealing bar includes corner partsprovided with said small leg portions and in that the free ends of thefurther leaf spring means are supported at said corner parts ahead ofthe small leg portions.
 7. A radial sealing bar according to claim 1,characterized in that the free ends of the leaf spring means are bent.8. A radial sealing bar according to claim 7, characterized in that thefree ends of the leaf spring means are bent outwardly.
 9. A radialsealing bar according to claim 7, characterized in that the free ends ofthe leaf spring means are bent inwardly.
 10. A radial sealing baraccordIng to claim 1, characterized in that the leaf spring means iscurved arcuately shaped.
 11. A radial sealing bar according to claim 10,characterized in that the leaf spring means is supported with its freeends at the upper wall portion within the hollow space means of thesealing bar and with its arcuate portion at the groove bottom of thegroove means.
 12. A radial sealing bar according to claim 10,characterized in that the leaf spring means is supported with itsarcuate portion at the upper wall portion in the hollow space means ofthe sealing bar and with its free ends at the groove bottom of thegroove means.
 13. A radial sealing bar according to claim 1,characterized in that the rotary piston internal combustion engine is oftrochoidal construction.
 14. A radial sealing bar according to claim 13,characterized in that the groove means is axially parallel.
 15. A radialsealing bar according to claim 14, characterized in that the hollowspace means extends approximately over the entire length of the sealingbar and is provided-as viewed in the longitudinal direction of thesealing bar-with two aperture means arranged one behind the other,through which projects the leaf spring means.
 16. A radial sealing baraccording to claim 15, characterized in that the leaf spring means iscurved arcuately shaped.
 17. A radial sealing bar according to claim 16,characterized in that the leaf spring means is supported with its freeends at the upper wall portion within the hollow space means of thesealing bar and with its arcuate portion at the groove bottom of thegroove means.
 18. A radial sealing bar according to claim 16,characterized in that the leaf spring means is supported with itsarcuate portion at the upper wall portion in the hollow space means ofthe sealing bar and with its free ends at the groove bottom of thegroove means.
 19. A radial sealing bar according to claim 16,characterized in that the leaf spring means is constructed three-arched,the center arcuate portion being supported at the upper wall portion ofthe hollow space means, the arcuate portions adjoining the centerarcuate portion being supported at the groove bottom and the free endsbeing supported at the sealing bar.
 20. A radial sealing bar accordingto claim 16, of multi-partite construction which includes corner parts,characterized in that the free ends of the leaf spring means aresupported under the corner parts.
 21. A radial sealing bar according toclaim 16, of multi-partite construction which includes small legportions, characterized in that underneath the arcuate portion of theleaf spring means projecting into the hollow space means of the sealingbar, a further leaf spring means is provided having a larger radius ofcurvature, whose free ends are supported at the sealing bar ahead of therespective small leg portions thereof.
 22. A radial sealing baraccording to claim 21, characterized in that the sealing bar includescorner parts provided with said small leg portions and in that the freeends of the further leaf spring means are supported at said corner partsahead of the small leg portions.
 23. A radial sealing bar according toclaim 21, characterized in that the free ends of the leaf spring meansare bent.
 24. A radial sealing bar according to claim 23, characterizedin that the free ends of the leaf spring means are bent outwardly.
 25. Aradial sealing bar according to claim 23, characterized in that the freeends of the leaf spring means are bent inwardly.